In the manufacture of paper on continuous papermaking machines, a web of paper is formed from an aqueous suspension of fibers (stock) on a traveling mesh of papermaking fabric and water drains by gravity and suction through the fabric. The web is then transferred to the pressing section where more water is removed by pressure and vacuum. The web next enters the dryer section where steam heated dryers and hot air complete the drying process. The paper machine is, in essence, a water removal, system. A typical forming section of a papermaking machine includes an endless traveling papermaking fabric or wire, which travels over a series of water removal elements such as table rolls, foils, vacuum foils, and suction boxes. The stock is carried on the top surface of the papermaking fabric and is de-watered as the stock travels over successive de-watering elements to form a sheet of paper. Finally, the wet sheet is transferred to the press section of the papermaking machine where enough water is removed to form a sheet of paper. Many factors affect the quality of the paper produced.
Papermaking machine operators often experience quality problems related to discrete portions of the paper sheet being produced. For example, wet streaks and light or heavy areas can develop on the paper. These quality problems are often detected by the quality control system but they are typically not evident to the operators when they simply observe the paper. To troubleshoot and understand the source(s) of the paper quality problems, it would be helpful to know exactly where the problems are located when an operator visually inspects the physical sheet, that is, when viewing the paper at the reel or other section along the papermaking machine.